Your toaster uses infrared radiation to crisp up your bread. When you see those toasty coils glow red, that’s the radiation. Infrared radiation is a type of electromagnetic radiation that sounds like it’s different from heat but it’s just heat. The coils provide a gentle drying and charring effect on the surface of your bread.

toasterMost toasters use nichrome wire wrapped back and forth across a mica sheet to heat up yo bread. Nichrome is an alloy of nickel with chromium (and sometimes iron) commonly used in high-temperature applications such as electrical heating elements. Its electrical resistance allows for it to generate a lot of heat when currents are run through it. Nichrome is also useful because it does not oxidize when it is heated (like iron would, leading to rust). ┬áMica is a shiny sillcate mineral with a layered structure generally found as minute scales in granite and other rocks, or as crystals. It’s used as a thermal or electrical insulator.

With a couple mica sheets wrapped in nichrome, you could get the toasty job done. However, things like bread crumb catchers and spring-loaded toast-announcing movements have come to be expected.

When you look deep into a toaster’s crevice, you’ll generally notice a metal holder rising up and down in the slots to raise and lower the bread as well as a pair of grates that line either side of both slots. When you push the holder down, metal springs at the bottom of either slot get compressed which in turn squeezes the grates inward, towards each other.

The handle is attached to the holders. When you push the handle down, a mechanism activates which holds the handle down until the toast is ready, electric current is sent through the nichrome wires, and a timer is initiated that counts down until the toast pops up.

fork in toasterHere’s how it happens: When you push the handle down, you complete a circuit that allows for electric current to flow through the nichrome wires. Another simple current made up of transistors, resistors and capacitors turns on and supplies power to the electromagnet. The electromagnet then attracts a piece of metal added to the handle, holding the bread down. Another simple circuit is responsible for acting as a timer. A capacitor charges through a resistor and when it reaches a certain voltage it cuts off the power to the electromagnet. Without the magnetic charge holding the piece of metal (and the toast) down, the springs at the bottom of the toaster release their tension and pop up the bread. The springs also push the plastic handle up, cutting off the power to the toaster all together.

A lot of toasters allow for toast darkness settings by using a variable resistor. Changing the resistance changes how fast the capacitor charges, which in turn affects how long it takes for the electromagnet to be cut off from the electricity that allows it to hold the piece of metal and the toast down into the toaster and maintain current flowing to the nichrome wires.

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